1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 1994 by Waldorf Electronics 7 * Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle 8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc. 9 * Copyright (C) 2007 Maciej W. Rozycki 10 */ 11 #include <linux/module.h> 12 #include <linux/param.h> 13 #include <linux/smp.h> 14 15 #include <asm/compiler.h> 16 #include <asm/war.h> 17 18 inline void __delay(unsigned int loops) 19 { 20 __asm__ __volatile__ ( 21 " .set noreorder \n" 22 " .align 3 \n" 23 "1: bnez %0, 1b \n" 24 " subu %0, 1 \n" 25 " .set reorder \n" 26 : "=r" (loops) 27 : "0" (loops)); 28 } 29 EXPORT_SYMBOL(__delay); 30 31 /* 32 * Division by multiplication: you don't have to worry about 33 * loss of precision. 34 * 35 * Use only for very small delays ( < 1 msec). Should probably use a 36 * lookup table, really, as the multiplications take much too long with 37 * short delays. This is a "reasonable" implementation, though (and the 38 * first constant multiplications gets optimized away if the delay is 39 * a constant) 40 */ 41 42 void __udelay(unsigned long us) 43 { 44 unsigned int lpj = current_cpu_data.udelay_val; 45 46 __delay((us * 0x000010c7ull * HZ * lpj) >> 32); 47 } 48 EXPORT_SYMBOL(__udelay); 49 50 void __ndelay(unsigned long ns) 51 { 52 unsigned int lpj = current_cpu_data.udelay_val; 53 54 __delay((ns * 0x00000005ull * HZ * lpj) >> 32); 55 } 56 EXPORT_SYMBOL(__ndelay); 57